poke: exit with status 3 on timeout

Change-Id: Idb021fe1fa1c3d40dbcfc87d4b1dadbea6cb28f6
diff --git a/tests/peek/ndnpoke.t.cpp b/tests/peek/ndnpoke.t.cpp
index 46f445d..cdcd262 100644
--- a/tests/peek/ndnpoke.t.cpp
+++ b/tests/peek/ndnpoke.t.cpp
@@ -195,7 +195,7 @@
 
   this->advanceClocks(io, 1_s, 4);
 
-  BOOST_CHECK(poke->getResult() == NdnPoke::Result::UNKNOWN);
+  BOOST_CHECK(poke->getResult() == NdnPoke::Result::TIMEOUT);
   BOOST_CHECK_EQUAL(face.sentData.size(), 0);
 
   // Check for prefix unregistration